In commercial communication systems, it is desirable to track call quality, e.g., as one or more measures of quality of service of communication links, because call quality is significant to user experience and to system stability. Monitoring call quality is used for provisioning networks and for properly allocating network resources. This is applicable to voice communication, e.g., voice communication over IP (VoIP), and to communicating other streams of media packets, e.g., streams of packets containing video and/or audio data.
One of the key reasons for degradation of quality is lost packets. When a real time stream of media packets is sent, e.g., a VoIP stream, at the receive side, there is a limit as to how long to buffer the arriving packets, e.g., in order to limit the delay. If a packet does not arrive within a pre-defined window of time, it is considered a lost packet. Modern networks may thus log and analyze statistics and/or other information that relate to packet loss. When packet loss is detected, packet loss concealment (PLC) may be used, and many methods for PCL are known. For example, many voice codecs include PLC, including, e.g., ITU-T G.722 codecs and others.
It is desired to obtain a measure of perceptual voice quality online at the receiving end of a communication link. One method of measuring call quality, e.g., as a measure of perceptual voice quality is to measure the statistics of lost packets, and/or other information on the lost packets, and to use such statistics and/or other information of lost packets to obtain a measure of perceptual voice quality for the link. Many methods are known for so determining a measure of perceptual voice quality online at the receiving end of a communication link. Because of PLC, and because of where in time a packet appears, some lost packets do not impact voice quality as much as others.
The approaches described in this BACKGROUND section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section. Similarly, issues identified with respect to one or more approaches should not assume to have been recognized in any prior art on the basis of this section, unless otherwise indicated.